Combined variable resistor and switch devices



D 1964 TAKAHO MATSUNAGA 3,161,847

COMBINED VARIABLE RESISTOR AND SWITCH DEVICES Filed Feb. 19, 1962 INVENTOR. Ta/(aho Maf'suna a QQJWQWLK United States Patent 3,161,847 CQMBINED VARIABLE RESISTOR AND SWITCH DEVICES Talraho Matsunaga, Osaka, Japan, assignor to Sanyo Electric Co., Ltd., Moriguchi-shi, Japan, and Yamano Electric Manufacturing Co., Ltd, Kawachi-shi, Japan,

both corporations of Japan Filed Feb. 19, 1962, Ser. No. 174,162 Claims priority, application Japan Nov. 9, 1961 Claims. (Cl. 338172) This invention relates to combined variable resistor and switch devices for use in small size electrical ap paratus, such as transistor radios.

Recent trend of minimizing sizes of electrical apparatus as above-mentioned requires combined variable resistor and switch devices: of compact construction with minimum dimensions, and such a device should be of simple construction for easy assembling, and at the same time, the closing and opening of the switch should be clearly perceivable by sense of touch or hearing to the person who operates the switch.

Accordingly, the primary object of the present invention is to provide a combined variable resistor and switch device of simple construction for easy assembling and of extremely small size, wherein the opening and closing of the switch is clearly preceivable by sense of the person who operates the switch.

There are other objects and particularities of the present invention which will be made obvious from the following description of an embodiment of the invention with reference to the accompanying drawings, in which;

FIG. 1 is a perspective view showing main parts of the combined variable resistor and switch device disassembled;

FIG. 2 is a top plan view of the device;

FIG. 3 is a side elevational view with the switch in closed position; and

FIG. 4 is a view similar to FIG. 3 and shows the switch in open position.

Referring to the drawings, a molded insulating casing 1 of fiat cylindrical shape encloses therein a variable resistor of conventional type. The variable resistor is provided with three terminal elements 2 and 2' secured rigid to the top surface of the casing 1 and extending radially outwardly beyond the periphery of the casing 1. Two outer terminal elements 2 are electrically connected to the opposite ends of the resistance element of the variable resistor, not shown, while the central terminal element 2' extends also radially inwardly and is provided with an enlarged inner end resting on the outer or upper wall surface of the casing 1 around its central bore, where an oval hole 25 is formed.

The shaft 9 is made of electrically conducting mateial and carries a contact brush, not shown, for rotation therewith to cooperate with the resistance element of the variable resistor. The shaft 9 passes through the central bore of the casing 1 and is provided with an annular collar 21 slidably engaging the inner wall surface of the casing 1 around its central bore. The shaft 9 is provided with another annular collar 22 for slidably engaging the inner enlarged end of the central terminal element 2' having the oval hole 25 through which the collar 22 can pass. After the collar 22 has passed through the hole 25, the terminal element 2 is shifted radially to have its inner end partly inserted into the annular groove defined between two collars 21 and 22 and contacting the shaft 9. The contact element 2' is then fixed in position to the casing 1. Thus, an electrical connection is established between the central terminal element 2' and the contact brush of the variable resistor through the shaft 9.

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. The switch portion of the device according to the invention comprises a pair of terminal elements 3 and 3 which are disposed angularly to each other and extend beyond the periphery of the casing 1 to provide also means for mounting the whole device in the electrical apparatus, such as a transistor radio receiver. The ter minal element 3 is secured rigidly to the top of the casing 1 by means of rivets 4, while the element 3' is fixed rigidly to the top of the casing 1 by means of rivet bolts 8 which also provide means for securing a resilient contact piece 6 to the casing 1 through a spacer member 7 and the terminal element 3'. The spacer member 7 is made of conducting material and serves to position the contact piece 6 high enough above the top surface of the casing 1 for the purpose to be described.

The contact element 3 has its inner end portion bent upwards substantially at a right angle, and the bent end 5 is shaped to a mountain to provide a pair of opposite cam slopes 13, and a flat top to cooperate with the free end of the contact piece 6 as electrical contacts.

The shaft 9 is provided with an annular shoulder 22 above the collar 21, and the upper end portion of the shaft above the shoulder 22 has a non-circular cross-section. The contact piece 6 has a hole through which the upper end of the shaft projects upwardly. The hole in the contact piece 6 is large enough to allow the shaft 9 to rotate freely in the hole.

According to the invention, there is provided an actuating plate 11 of substantial thickness and of an elongated configuration. It is made of insulating material. The plate 11 is provided in its root portion with a noncircular opening 12 corresponding to the cross-sectional shape of the upper end portion of the shaft 9. The insulating plate 11 is mounted on the shaft 9 below the contact piece 6 and rotatably therewith by fitting of the hole 12 about the upper non-circular end portion of the shaft 9. However, it is to be noted that the plate 11 is swingable upwardly with respect to the shaft 9 to a certain extent.

The free end 14 of the actuating plate 11 is formed to a fork shape and is positioned at such a radial distance from the shaft 9 that the forked end 14 may cooperate with the cam slopes 13 of the terminal element 3.

The shaft 9 has its lower end 23 formed to noncircular cross-section, which fits in a corresponding recess, not shown, formed in the operating knob disc 10 for rotation therewith. The knob disc 10 is fixed to the shaft 9 by means of a screw 24. Thus, by manually rotating the knob disc 10, the switch may be actuated to open and close, and at the same time, the variable resistor may be adjusted for volume adjustment of a radio receiver, for example, as hereinafter described.

In FIG. 3, the switch is shown in the closed position with the free end of the resilient contact piece 6 engaging the flat top of the bent end 5 of the terminal element 3. At this position, the free end of the actuating member 11 is positioned away from the end 5, and the shaft 9 is free to rotate for adjustment of the variable resistor. In order to open the switch which may be a main switch of a radio receiver, for example, the knob disc 10 is rotated in one direction to bring the free end 14 of the actuating member 11 in contact with a cam slope 13 of the bent end 5 of the terminal element 3. A further rotation of the shaft 9 causes the free end 14 of the actuating member 11 to ride on the cam slope 13, and the actuating member 11 is tilted as shown in FIG. 4, finally entering into the space between the fiat top of the bent end 5 and the free end of the resilient contact piece 6, with the two legs of forked end 14 astriding the mountain top. Since the actuating plate is of insulating material of substantial thickness, the electrical switch is thus actuated and kept open.

When the switch is actuated open as above, the astriding motion of the forked end 14 of the actuating member 11 against the resilient force of the contact piece 6 on the mountain top of the bent end provides clearly percei'vabl'e sense of touch to the person who is operating the knob disc 1 0. In order to close the switch, the knob disc is rotated to the opposite direction,- andthe forked end 14 of the actuating member 11 goes out of the bent end 5 of the terminal element 3, upon which the free end of the resilient contact piece 6 strikes strongly the flat top of the bent end 5, thus producing a clearly perceivable sound and make the electrical contaCtS';

I- claim:

1-. A combined variable resistor and switch device comprising a casing,- a resistance element enclosed in said casing, a rotatable operating shaft mounted through said casing, means carried by said shaft for rotation therewith in said casing to cooperate with said resistance element for forming a variable resistor, a pair of terminal elements fixedly mounted to an end face of said casing, a resilient electrical contact member, means for securing one end of said resilient contact member to said end face in electrical connect'ionwith one of said terminal elements, the other of said terminal elements having an upwardly bent end provided With at least one sloping surface on the side thereof, the free end of said resilient contact member engaging the top of said upwardly bent end to close an electrical circuit across said terminals,

and an actuating member of insulating material mounted on said shaft for rotation therewith and free to swing up and down with respect to said shaft, rotation of said shaft to a predetermined position causing the free end of said actuating member to ride up a sloping surface of the upwardly bent end of said other terminal element and move said electrical contact member out of engagement with said other terminal to open the electrical circuit across said terminals.

2; The device according to claim 1 wherein the free end of said actuating member has a cutout portion into which the top of the upwardly bent end protrudes when the contact member is out of engagement with the said other terminal.

3. The device according to claim 2 wherein said free end of said actuating member is fork-shaped.

4. The device according to claim 1, in which said resilient contact member has a hole through which said rotatable shaft freely passes.

5. The device according to claim 1, in which said actuating member has a substantial thickness and is pro vided with a non-circular opening in which a correspondingly shaped portion of said shaft is positioned so as to prevent relative rotation of said actuating member and said shaft but to allow a certain degree of u'p-and-down swing of said actuating member.

References Cited in the file of this patent UNITED STATES PATENTS 1,716,513 Briggs June 11, 1929 2,133,858 Hathorn Oct. 18, 1938 2,159,369 Draving et a1. May 23, 1939 2,451,241 Rosentreter Oct. 12, 1948 

1. A COMBINED VARIABLE RESISTOR AND SWITCH DEVICE COMPRISING A CASING, A RESISTANCE ELEMENT ENCLOSED IN SAID CASING, A ROTATABLE OPERATING SHAFT MOUNTED THROUGH SAID CASING, MEANS CARRIED BY SAID SHAFT FOR ROTATION THEREWITH IN SAID CASING TO COOPERATE WITH SAID RESISTANCE ELEMENT FOR FORMING A VARIABLE RESISTOR, A PAIR OF TERMINAL ELEMENTS FIXEDLY MOUNTED TO AN END FACE OF SAID CASING, A RESILIENT ELECTRICAL CONTACT MEMBER, MEANS FOR SECURING ONE END OF SAID RESILIENT CONTACT MEMBER TO SAID END FACE IN ELECTRICAL CONNECTION WITH ONE OF SAID TERMINAL ELEMENTS, THE OTHER OF SAID TERMINAL ELEMENTS HAVING AN UPWARDLY BENT END PROVIDED WITH AT LEAST ONE SLOPING SURFACE ON THE SIDE THEREOF, THE FREE END OF SAID RESILIENT CONTACT MEMBER ENGAGING THE TOP OF SAID UPWARDLY BENT END TO CLOSE AN ELECTRICAL CIRCUIT ACROSS SAID TERMINALS, AND AN ACTUATING MEMBER OF INSULATING MATERIAL MOUNTED ON SAID SHAFT FOR ROTATION THEREWITH AND FREE TO SWING UP AND DOWN WITH RESPECT TO SAID SHAFT, ROTATION OF SAID SHAFT TO A PREDETERMINED POSITION CAUSING THE FREE END OF SAID ACTUATING MEMBER TO RIDE UP A SLOPING SURFACE OF THE UPWARDLY BENT END OF SAID OTHER TERMINAL ELEMENT AND MOVE SAID ELECTRICAL CONTACT MEMBER OUT OF ENGAGEMENT WITH SAID OTHER TERMINAL TO OPEN THE ELECTRICAL CIRCUIT ACROSS SAID TERMINALS. 